1. Field of the Invention
The present invention relates to a seat cushion of a vehicle seat. Specifically, the invention is directed to a seat cushion of the type comprising a seat cushion frame and a bottom panel member substantially underlaying the seat cushion frame, with the ends of the bottom panel member being connected with frame members of the seat cushion frame.
2. Description of Prior Art
In general, a vehicle seat is basically composed of a seat cushion for supporting a buttocks and thigh portions of seat occupant and a seat back for supporting a back portion of the seat occupant. With regard to the seat cushion in particular, among various seat cushions, there has been known a seat cushion of the type having a bottom panel member provided in the bottom side thereof, the bottom panel member being mainly adapted for supporting a foam padding thereon. More specifically, the seat cushion of this type basically comprises a seat cushion frame and a bottom panel member, such that the bottom panel member is disposed in a space surrounded by frame members of the seat cushion frame so as to be situated underside of the seat cushion frame, with the peripheral ends of the bottom panel member being connected to the frame members.
In some of the seat cushions of this kind, the peripheral ends of the bottom panel member are fixedly attached by welding to the seat cushion frame. On the other hand, there are some seat cushions wherein the peripheral ends of the bottom panel member are connected by springs to the seat cushion frame, such that the bottom panel member is resiliently suspended from the seat cushion frame, which is for example disclosed from the Japanese Laid-Open Patent Publication No. 2007-99195 or JP 2007-99195 A1. Further, in some other seat cushions of this kind, a bottom panel member used is made of a spring material, and therefore, a whole of the bottom panel member itself is elastic and prone to resilient deformation, as disclosed from the Japanese Laid-Open Patent Publication No. 2005-237519 or JP 2005-237519 A1 for instance.
However, the above-described conventional seat cushions have been with their own inevitable problems, which are set forth as follows:
(i) In the case of the seat cushion having the bottom panel member welded to the seat cushion frame thereof, the cushiony effect of the seat cushion is insufficient due to the rigid formation of the bottom panel member, thus requiring an increased thickness of a foam padding mounted on the bottom panel member to attain a satisfied cushiony effect of the seat cushion. Consequently, such increased thickness of foam padding results in the seat being correspondingly increased in size and therefore makes narrow a space of vehicle in which the seat is disposed.
(ii) In the case of the seat cushion (e.g. JP 2007-99195 A1) wherein a bottom panel member is connected by springs to a seat cushion frame, the construction of the seat cushion is rather complicated and requires a great number of parts and many steps of assembly for forming the seat cushion. This is apparently time-consuming and undesired increase of costs involved.
(iii) As for the seat cushion (e.g. JP 2005-237519 A1), the bottom panel member itself is made of spring material and the entirety thereof is resiliently deformable, which undesirably gives a cushiony effect even to the areas of seat cushion that do not require any cushiony and resilient touch, such as an area of seat cushion for supporting thigh portions of seat occupant thereon, for instance.